[Distribution of amino acid residue conformation in three-dimensional protein structures. Analysis of the non-glycine residues in "positive" conformations].

The analysis of amino acid residue conformations occurring in 81 three-dimensional (3-D) X-ray protein structures have been made. It has been revealed that a relatively great number of non-glycine residues in positive conformation may be considered as a simple criterion pointing to the presence at least of local errors in the structure. The number of 3-D protein structures have been specified, that contains some local errors. Based on the literature data analysis results, and on the results of residue molecular geometry analysis, it has been shown that many of the non-glycine residues in positive conformations have a poorly determined atomic coordinates: they are involved in the ill determined segments of the polypeptide chains, or display a higher or high temperature factor. Some of the others left-handed non-glycine residues have a non-rigid molecular geometry, or are in the energetically unfavorable conformations. Based on the obtained results, made the assumption that the non-glycine residues in a 3-D protein structure should be occur only in the negative conformations.